Neuromuscular and Biomechanical Control of Lower Limb Loading in Individuals With Chronic Stroke
| Status: | Recruiting |
|---|---|
| Conditions: | Neurology |
| Therapuetic Areas: | Neurology |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 2/27/2019 |
| Start Date: | February 4, 2019 |
| End Date: | December 31, 2020 |
| Contact: | Vicki Gray, PhD |
| Email: | vicki.gray@som.umaryland.edu |
| Phone: | 410-706-3778 |
Stroke is the leading cause of long-term disability in the U.S. Individuals with hemiparesis
due to stroke often have difficulty bearing weight on their legs and transferring weight from
one leg to the other. The ability to bear weight on the legs is important during functional
movements such as rising from a chair, standing and walking. Diminished weight transfer
contributes to asymmetries during walking which commonly leads to greater energy expenditure.
Moreover, deficits in bearing weight on the paretic leg contribute to lateral instability and
are associated with decreased walking speed and increased risk of falling in individuals
post-stroke. These functional limitations affect community participation and life quality.
Thus, restoring the ability to bear weight on the legs, i.e., limb loading, is a critical
goal for rehabilitation post-stroke. The purpose of this research is to identify the
impairments in neuromechanical mechanisms of limb loading and determine whether limb loading
responses can be retrained by induced forced limb loading.
due to stroke often have difficulty bearing weight on their legs and transferring weight from
one leg to the other. The ability to bear weight on the legs is important during functional
movements such as rising from a chair, standing and walking. Diminished weight transfer
contributes to asymmetries during walking which commonly leads to greater energy expenditure.
Moreover, deficits in bearing weight on the paretic leg contribute to lateral instability and
are associated with decreased walking speed and increased risk of falling in individuals
post-stroke. These functional limitations affect community participation and life quality.
Thus, restoring the ability to bear weight on the legs, i.e., limb loading, is a critical
goal for rehabilitation post-stroke. The purpose of this research is to identify the
impairments in neuromechanical mechanisms of limb loading and determine whether limb loading
responses can be retrained by induced forced limb loading.
Stroke is the leading cause of long-term disability in the U.S. Individuals with hemiparesis
due to stroke often have difficulty bearing weight on the paretic lower extremity and
transferring weight from one leg to the other. Impaired weight transfer and limb loading
contribute to lateral instability and are associated with decreased walking speed and
increased risk of falling. Consequently, restoring limb loading ability is an important goal
for rehabilitation post-stroke. Despite considerable rehabilitation efforts aimed at
enhancing paretic limb loading, their effectiveness on improving neuromotor and functional
outcomes remains limited possibly due to poorly understood limb loading mechanisms and the
reluctance to use the paretic limb. The coordination of neuromuscular actions to regulate
loading force during weight acceptance is an important component of functional limb loading.
Because altered neuromuscular control is common in persons with stroke, it is possible that
these abnormalities may impair limb loading ability. The long-term objective of this project
is to develop a mechanism-based framework for designing and testing the effectiveness of
novel rehabilitation interventions to enhance lower limb weight transfer and limb loading to
improve balance and mobility. This project aims to (1) identify the neuromuscular and
biomechanical abnormalities in limb loading responses in individuals post-stroke, (2)
determine the underlying mechanisms responsible for the deficits in limb loading, and (3)
test the short-term effectiveness of a 6-week perturbation-induced limb load training program
on improving limb loading responses and mobility function. The investigators propose to apply
a sudden unilateral lowering of the supporting surface to induce lateral weight transfer that
forces limb loading. Kinetic, kinematic, and lower extremity muscle activation patterns will
be recorded. The investigators expect that, compared to healthy controls, individuals with
stroke will show increased muscle co-activation of the knee musculature with decreased knee
flexion and torque production, and irregular impact force regulation during loading that will
disrupt weight transfer and loading of the paretic limb. Furthermore, the investigators
hypothesize that compared to a conventional clinical weight-shift rehabilitation training
program, the imposed limb loading group will show greater improvements during voluntary
stepping and walking following training. Specifically, the investigators expect the knee
muscle co-activation duration will be reduced, with increased knee joint torque, and the
paretic single stance/double support time will increase, reflecting improved paretic limb
loading ability during gait following training.
due to stroke often have difficulty bearing weight on the paretic lower extremity and
transferring weight from one leg to the other. Impaired weight transfer and limb loading
contribute to lateral instability and are associated with decreased walking speed and
increased risk of falling. Consequently, restoring limb loading ability is an important goal
for rehabilitation post-stroke. Despite considerable rehabilitation efforts aimed at
enhancing paretic limb loading, their effectiveness on improving neuromotor and functional
outcomes remains limited possibly due to poorly understood limb loading mechanisms and the
reluctance to use the paretic limb. The coordination of neuromuscular actions to regulate
loading force during weight acceptance is an important component of functional limb loading.
Because altered neuromuscular control is common in persons with stroke, it is possible that
these abnormalities may impair limb loading ability. The long-term objective of this project
is to develop a mechanism-based framework for designing and testing the effectiveness of
novel rehabilitation interventions to enhance lower limb weight transfer and limb loading to
improve balance and mobility. This project aims to (1) identify the neuromuscular and
biomechanical abnormalities in limb loading responses in individuals post-stroke, (2)
determine the underlying mechanisms responsible for the deficits in limb loading, and (3)
test the short-term effectiveness of a 6-week perturbation-induced limb load training program
on improving limb loading responses and mobility function. The investigators propose to apply
a sudden unilateral lowering of the supporting surface to induce lateral weight transfer that
forces limb loading. Kinetic, kinematic, and lower extremity muscle activation patterns will
be recorded. The investigators expect that, compared to healthy controls, individuals with
stroke will show increased muscle co-activation of the knee musculature with decreased knee
flexion and torque production, and irregular impact force regulation during loading that will
disrupt weight transfer and loading of the paretic limb. Furthermore, the investigators
hypothesize that compared to a conventional clinical weight-shift rehabilitation training
program, the imposed limb loading group will show greater improvements during voluntary
stepping and walking following training. Specifically, the investigators expect the knee
muscle co-activation duration will be reduced, with increased knee joint torque, and the
paretic single stance/double support time will increase, reflecting improved paretic limb
loading ability during gait following training.
Inclusion Criteria:
- Hemiparesis as a result of a stroke greater than 6 months previous to the study if
participants with stroke.
- Able to walk 10 meters with or without a walking aid.
- Able to stand unsupported for 5 minutes.
Exclusion Criteria:
- Medical condition precluding participation in regular exercises, such as acute cardiac
or respiratory conditions limiting activity and other health conditions significantly
impacting the ability to walk beyond the effects of the stroke, such as other
neurological conditions or peripheral neuropathies.
- Not able to follow commands.
- Pregnancy by self-report.
We found this trial at
1
site
Baltimore, Maryland 21201
Principal Investigator: Vicki L Gray, MPT, PhD
Phone: 410-706-3778
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